Abstract
INTRODUCTION: Depression is the most common mental disorder in sub-Saharan Africa (SSA). Group interpersonal therapy (IPT-G) is a recommended first-line treatment for depression, shown to be safe and effective in clinical trials. However, less is known about its real-world retention and effectiveness when delivered at scale in SSA. We describe retention patterns and associated factors in a large IPT-G programme in Uganda and Zambia. METHODS: We analysed routine data from adults (≥18 years) who initiated community-based IPT-G in Uganda and Zambia (2020-2021). Depressive symptoms were assessed using the Patient Health Questionnaire (PHQ-9), and individuals with probable depression were offered IPT-G. We classified clients based on their attendance across eight IPT-G sessions using latent class analysis. Sociodemographic and programme-related factors associated with latent classes were examined using multinomial logistic regression. Changes in PHQ-9 scores from pretreatment to post-treatment were compared across latent classes. Statistical significance of differences was assessed using the Wald χ(2) test. RESULTS: Among 45 349 clients, overall average attendance was 82%. Four classes emerged from attendance patterns: high attendance (63%), moderate attendance (27%), early dropout (6%) and late dropout (4%). Relative to the high attendance class, the early drop-out class had higher odds of being age <25 (adjusted OR (aOR) 1.19, 95% CI 0.99 to 1.44), in teletherapy (aOR 3.46, 95% CI 2.89 to 4.13) and presenting with moderate than moderately severe to severe depression (aOR 1.27, 95% CI 1.17 to 1.40). The overall mean reduction in PHQ-9 scores was 13.0 (SD 4.2), but the early drop-out group showed smaller improvements (10.32, SD 8.78) compared with the high attendance group (13.3, SD 6.15, p=0.001). CONCLUSION: Retention in a scaled IPT-G programme in Uganda and Zambia was high. Still, early dropout-linked to younger age, teletherapy and moderate depression-was associated with less reduction in depressive symptoms. These findings highlight areas for innovation in IPT-G implementation to improve engagement and outcomes.